Magnolia iltisiana A.Vazquez
-
Authority
Vázquez García, J. Antonio. 1994. Magnolia (Magnoliaceae) in Mexico and Central America: A Synopsis. Brittonia. 46 (1): 1-23.
-
Family
Magnoliaceae
-
Scientific Name
-
Description
Latin Diagnosis - Arbores 20-40 (45) m altae, trunci usque 1.5 m diam.; ramuli ultimi dense fulvo-velutini; folia oblonga; lamina 17-22 (25) cm longa, 4.5-8 (10) cm lata, supra viridis glabra, lucida, subtus glauco-pubescens, petioli dense fulvo-velutini; stipulae 3.5-8 cm longae, 3-10 mm latae, extis pubescentes; alabastra usque 16 cm diam.; bracteae 2-3, fulvo-velutinae; sepala ebumea, oblonga, extus pubescentia; petala ebumea, anguste obovata vel anguste spathulata; fructus ovoidei vel subglobosi, 4.3-5 (6) cm longi, 3.3-4.4 cm lati; folliculi (32) 35-38 (42), dense fulvo-velutini; semina coccinea, prismatica vel rotunda.
Species Description - Trees 20-40 (45) m tall, 60-150 cm dbh, with first branches at 4-15 m from the base; twigs densely pale yellowish velutinous to felted; bark scabrous or smooth, 1-1.5 cm thick, gray. Leaves coriaceous, elliptic to oblong-lanceolate, 17-22(25) cm long, 5-8 (10) cm wide, acute to acuminate at apex, narrowly to broadly cuneate, glabrous to glabrate and lustrous light to dark green above, whitish pubescent and pale green to glaucous beneath; stipules linear, 3.5-8 cm long, 3-10 mm wide, yellowish-greenish pubes- cent without, glabrous within, with reddish- brown venation; petiole canaliculate, 1.8- 2.5 (3 cm) long, yellowish velutinous to felt- ed. Flower buds ovoid-oblong, enclosed by 2 or 3 bracts, the uppermost spathaceous, ovoid-oblongoid, 3.5-4.3 (5) cm long, 1.8- 2.3 (2.7) cm in diam., velutinous to felted without and glabrous within, pale yellowish, the next lower spathaceous, ovoid-oblon- goid, 4-5 (5.4 cm) long, 1.8-2.3 (2.5) cm in diam., of similar pubescence, the lowermost (perule) shortly oblong, 1.4-2.7 cm long, 8- 10 mm wide, of similar pubescence; open flowers 11-14 cm in diam., creamy white; peduncle 8-25 mm long, 6-8 mm thick, densely pale yellowish velutinous to felted, consisting of 2 internodes, the upper hidden by a kind of cupular annular scar, with the length of the lower internode, therefore, equaling the length of the peduncle; sepals 3, oblong-elliptic, laterally projected and slightly concave, shorter than the petals, 5- 6 cm long, 1.8-2.3 (2.6) cm wide, adaxially glabrous, abaxially pale yellowish velutinous to felted towards the base of the claw, both surfaces creamy white when fresh; petals 6, obovate, cuneate towards the claw, flat or some of them concave, 7-8 cm long, 2.5-3.5 cm wide, with few scattered hairs towards the claw, creamy white on both sur- faces; stamens ca. 90-100, 12.5-13.5 mm long, 1-2 mm wide, acute at the apex; gy- noecium subglobose, yellowish-greenish velutinous to felted; styles linear and recurved, white throughout, with papillae evident, becoming black, some of them persistent. Polyfollicles subglobose to oblong, 4.3-5 (6) cm long, 3.3-4.4 cm wide; follicles (32) 35- 38 (42), to 2.4 cm long, densely yellowish velutinous to felted without, the lignified style often persistent; seeds triangular-prismatic to rotund-compressed, 10-12 mm long, 6-9 mm wide, with a bright red sarcotesta
-
Discussion
TYPE: MEXICO. Jalisco: Sierra de Manantlan, NE-facing slopes above Arroyo Las Joyas, 1.5 km W of Estacion Cientifica Las Joyas [El Zarzamoro], on road to Ahuaca- pan, 19º35'10"N, 104º17'03"W, 20 Mar 1989 (fr), T. S. Cochrane, M. A. Wetter & F. J. Santana-M. 11702 (HOLOTYPE: WIS!; ISOTYPES: BH!, BM!, IBUG!, LE!, MEXU!, MICH!, NY!, US!, XAL!, ZEA!).
J. E. Dandy was perhaps the first to in- dicate, by annotations in 1927, that some herbarium specimens with dense indumen- tum from Sinaloa and Michoacan repre- sented a new taxon, yet he was quite incon- sistent in his application. Much later, H. Iltis, and perhaps R. McVaugh as well, also suspected independently that specimens from Sierra de Manantlan, Jalisco, constitute an undescribed species. Though similar to M. tamaulipana and M. grandiflora, M. iltisiana is perhaps most closely related to the Central American M. sororum, which has more oblongoid fruits, larger stipules, much smaller flowers, and narrower petals and sepals.
Open flowers have been found from late March to late June or early July and are pollinated by chrysomelid beetles. Only a few of them mature into fruits that dehisce by September of the same year, most of them over-wintering in the undehisced state and dehiscing during late February or early March of the following year (A. Solis-M., pers. comm.). A few follicles located on the sun-facing side of the fruit may dehisce when the polyfollicles are still on the tree, but many of them will not complete dehiscence until they are on the ground. Several species of squirrels gnaw on the nearly mature fruits to obtain the seeds while the fruits are still attached, no matter how woody the fruits are. Once on the ground the fruits undergo a quick degradation by fungi such as Mycena, Tricholoma, and Xylaria (G. Nieves-H., pers. comm.), so that most of them will be completely decayed before the next fruiting season. The seeds are produced in tremendous quantities, per- haps to overwhelm predators and increase chances of survival; however, they have a short longevity (10-1 5 days), low viability, and also are heavily predated by squirrels, which peel off the hot-spicy fleshy seed cover (sarcotesta), break the hard slippery cover (sclerotesta), and eat the oily, protein-rich seed interior. The same situation was observed by Iltis in M. tamaulipana at Rancho del Cielo in 1991. Only very few seedlings live to adult stage.
Human uses: In the 1980's the logs of these trees were sold to Germany for veneer, and, in fact, they are still being cut in var- ious places because of the durability of the wood. Furthermore, this species, as well as many other Magnolia and Talauma species, are extremely valuable ancient indigenous medicines (Hernandez, 165 1) used to strengthen the heart and to help problems related to high blood pressure.
Conservation status: Threatened. According to preliminary observations, four biological factors (in addition to human-re- lated ones) seem to limit populations of this species from further expansion into equivalent habitats: excessive seed foraging by squirrels, quick degradation of indehisced fruits while maturing on the ground, its apparent gap-phase regeneration behavior (shade-intolerance), and, as in many other Magnolia species, the low dispersability of the relatively large seeds. It is noteworthy that the discovery by R. Guzman-M. and H. Iltis in January 1984 (pers. comm.) of some 25 Magnolia trees (some possibly over 200 years old) illegally marked for cutting provided the final and direct impetus for the purchase of the 1200 ha Estacion Cien- tifica Las Joyas by the State of Jalisco Gov- ernment for the University of Guadalajara, and thus, eventually, the preservation of the biota of these mountains within the 341,000 ha Sierra de Manantlan Biosphere Reserve.
Eponymy: Named in honor of my advisor, Hugh H. Iltis, of the University of Wisconsin-Madison, who has had a great interest not only in this species but also in the in situ preservation of nature, especially in the Sierra de Manantlan (Guzmain & Iltis, 1991).
Local names: "ahuatoso" (Guizard & Niembro 370), "laurel" (Koelz & McVaugh 926), "magnolia" (Cuevas & Rosales 1888), and "yoloxochitl" (Soto-N. 5247).
Representative specimens examined (* specimens from Sierra de Manantlan Biosphere Reserve, SMBR): MEXICO. Jalisco: Autlan, 7 km S of Ahuacapan, 22 Nov 1959 (fr), Koelz & McVaugh 926* (MICH), 2-3 km E of Corralitos, 19º36º50'N, 104º16º27'W, 2 Mar 1988 (fr), Cuevas & Nuiiez. 2293* (ZEA); Manantlan, 6 Feb 1983 (fr), Mc Vaugh 26581* (IBUG, MICH, ZEA); Autlan (Estaci6n Cientifica Las Joyas), El Zarzamoro, 10 Mar 1987 (fr), Iltis et al. 29432a* (WIS, ZEA), 5 Nov 1983 (fr), Perez de la R. 334* (IBUG, WIS), 6 Jun 1984 (fl, fr), Safnz-Ch. et al. 127, 130* (both IBUG, WIS), Los Barbechos, 14 Aug 1984 (fl), Guzmdn-M. 7008* (IBUG, WIS, ZEA), 19º35'N, 104º16'30'W, 24 Dec 1984 (fr), Cochrane & Judziewicz. 10695* (IBUG, WIS), 1.5-2 km NE of El Zarzamoro, 1 Jan 1984 (fr), Iltis et al. 29057* (IBUG), Ojo de Agua del Tlacuache, 9 Jun 1985 (fl, fr), Vdzquez-G. et al. 3005* (ZEA), La Cascada-Las Galeras, 10 Jun 1985 (fl), Vdzquez-G. et al. 3021* (ZEA), Las Mantequillas, ECLJ, 3 Jul 1986 (fl), Cuevas et al. 1482* (WIS, ZEA), Arroyo El Chilacayote-La Piedra Bola, 23 Dec 1984 (fr), Judziewicz & Cochrane 4928* (IBUG, WIS, ZEA); Ayutla, Sierra de Cacoma, La Platanillera, 11 km al SW de Las Ig- lesias, 25 Jan 1979 (fr), Guizard & Niembro 370, 379 (CHAPA, IBUG, XAL); Cuautitlan, Cerro Chilillas, 19º35'N, 104º14º30'W, 25 Dec 1984 (fr), Judziewicz & Cochrane 4986* (IBUG, WIS), Cerro La Cumbre, 2 Jan 1980 (fr), Iltis et al. 2235* (IBUG, WIS), SW of La Cumbre, 22 Mar 1965 (fr), McVaugh 23183* (MICH), NE of El Durazno, 31 Jan 1970 (fr), Boutin & Kimnach 3015* (CAS, MEXU), ENE de El Durazno, 22 Sep 1978 (fr), Iltis et al. 456* (IBUG), 1-4 km E of El Durazno, 6 Apr 1987 (fl, fr), Cuevas et al. 1888*, 1916* (both WIS, ZEA), Barranca La Nogalera, 27 Sep 1986 (fr), Vdzquez-G. et al. 4037* (ZEA), La Huertita, 19 Nov 1978, Martfnez-S. 480* (IBUG), 6 Jan 1979, Iltis et al. 1283* (IBUG), Arroyo La Paloma, 8 Mar 1988 (fr), Cuevas et al. 2832* (ZEA), 7 km al NW of Telcruz, Ayotitlan, 10 Feb 1988 (fr), Cuevas & L6pez- V. 2164* (IBUG, ZEA); Villa de Purificaci6n, Cerro El Remudadero, Dfaz-L. 11040 (GUADA). Michoacan: Cerro del Hayo, Charo, SW of Las Mesas, 8 May 1987 (fr), Santos-M. 2061 (IEB); Barranca Verde, Cerrito Tijera, Ejido Tuimbisca, Morelia, 4 Oct 1985 (fr), Madrigal-S. 4078 (EBUM, IBUG), 12 Jul 1989 (fr), Vdzquez-G. et al. 5017 (WIS); Carrindapaz, 9 Mar 1911, Arsene 97, s.n. (C, E, F, KEW); Cerro Azul, 4 Nov. 1909 (fr), Arsene 2836 (US), 1910 (fl), Arsene 5765 (MO, US); Rancho Parritas, 23 Feb 1985 (fr), Madrigal-S. 3915 (EBUM, IBUG), 24 Sep 1985 (fr), Madrigal-S. 4069 (EBUM, IBUG), 12 Jul 1989 (fr), Vdzquez-G. et al. 5018a-c (WIS). Guerrero: El Ran- chito, Atoyac de Alvarez, 11 km NE of Paraiso, 5 Jun 1983 (fl), Martfnez-S. et al. 5247 (MEXU, MO); Rio Verde-Paraiso, on road to Atoyac, 17º23'N, 100º16'W, 23 May 1989 (fl), Miller & Campos 2949 (MO, WIS); Atoyac-Puerto del Gallo, 9 km NE of Paraiso, 22 Nov 1983 (fr), Martfnez & Barrie 5576 (MEXU, MO); Puer- to del Gayo-Cruz de Ocote, Atoyac, 11 Jul 1988 (fr), Vdzquez-G. et al. 4901 (WIS)
-
Distribution
From Jalisco to Guerrero, in the Sierra Madre del Sur from 800 to 2440 m (Fig. 1). Locally abundant in moist subdeciduous cloud forests, mostly in ravines (barrancas) with Podocarpus reichei Bunch. & Gray, Matudaea trinervia Lundell, Symplococarpon purpusii (Brand.) Kobuski, Carpinus tropicalis Furlow, Quercus spp., and Cornus disciflora DC.; at higher elevations with Abies religiosa var. emarginata Loock & Martinez, Ostrya virginiana (Mill.) K. Koch, and Ternstroemia lineata DC.; at lower eleva
Mexico North America|